Contamination of sand by the base soil and the shifting of bunker sand during rain events in golf bunkers are widely known problems. Golfers generally prefer thinner layers of sand in bunkers as it increases the chance of executing a good shot out of the bunker. Therefore, a thin layer of sand in a bunker is preferable. In addition, when a bunker is constructed, a thin layer of sand is less expensive to apply on the surface of the bunker than a thick layer, since the total volume of sand that is needed is smaller for such a thin layer. However, a thin layer of sand is more susceptible to be mixed with the underlying soil. Moreover, a thin layer of sand has poorer drainage property than a thick layer of sand, which may result in water and sand accumulating at the bottom of the bunker after a heavy rain. Another problem with a thin layer of sand is that the sand will at least partly run off the generally relatively steep side slopes of the bunker.
A solution to the problem is to use a water permeable fabric as a liner that is applied on the ground/soil before the application of the bunker sand. However, there are several problems when using such a fabric. For instance, when a golf player is hitting the ball in a bunker he may also hit the underlying fabric, hence there is a risk that the fabric will move in relation to the sand and the soil. Such a movement may result in that the fabric will be visible by sticking up out of the sand. In addition, the players by mistake hitting the fabric, results in that the fabric will be worn out and break up. Thus, the fabric needs to be changed. An average lifetime of a fabric is about five to seven years. The problems with movements of the fabric are even larger in regions where the ground will freeze during winters, since the freezing of the ground increases the risk of movements of the fabric, and thus also the risk of exposure of the fabric to golf shots.
A solution to the problem is disclosed in WO2007070913, in which a base for a playing field is disclosed. The base for a playing field may be used for golf bunkers and comprises a layer of particulate material, said layer forming at least an upper part of the base, and a binder applied to the layer of particulate material, the binder extending from about 5 mm to about 150 mm into the layer of particulate material, the binder acting to bind at least the uppermost part of the layer of particulate material, said layer being porous to water such that water applied to a surface of the base flows through said layer. However, it has turned out that there are several problems with such a base for a playing field. One problem is formation of cracks. That is, when the base is exposed for water during long periods, such as during rainy periods in Nordic countries, the base will first become soft and thereafter crack. Moreover, the binder of the base is difficult to apply to the surface and setting of the binder is troublesome, since for best possible setting of the base it is preferable that the base is not exposed to water during setting. This may be difficult to achieve, since the total time before the base is completely set is about 7 days. Still another problem is that the lifetime of the base is not satisfying.
Hence, there is a need for improved methods for foundation of golf bunkers, and more specifically that overcomes or at least alleviates the prior art problems of golf bunker bases or liners.